As 3D televisions have come into widespread use, 3D image content has come into widespread use and transmission of 3D image content by a digital broadcast as well as by a storage medium has been activated.
In general, a 3D image provides a stereoscopic effect using the principle of stereo vision of two eyes. Since a human feels a perspective effect through binocular parallax due to an interval between the eyes spaced apart from each other by about 65 mm, a 3D image is provided such that a left eye and a right eye view respective plan images, thereby providing a stereoscopic effect and a perspective effect.
Examples of a 3D image display method include a stereoscopic method, a volumetric method, a holographic method, etc. In the stereoscopic method, a left view image to be viewed by a left eye and a right view image to be viewed by a right eye are provided and the left eye and the right eye respectively view the left view image and the right view image through polarized glasses or a display device, thereby perceiving a 3D image effect.
In case of 3D stereoscopic image content, when two similar images having different views are received, a reception device displays the two images as a 3D image. At this time, a method of sending the two similar images having different views via an existing broadcast channel or a method of respectively sending the two similar images having different views via an existing broadcast channel and a separate transport channel may be used. In this case, in order to enable a reception device to display the two images as a 3D image, signal information of the two images forming a pair must be received. If such information is not received, a left view image and a right view image forming one 3D image may not be distinguished so as not to restore the 3D image. In addition, it is difficult to know synchronization times of the left view image and the right view image and when a 3D image may be displayed.